The Naval Postgraduate School in Monterey, California launched an investigation into Clarke’s thesis after a CNN KFile report in May that claimed the content was plagiarized, the news outlet writes. The probe revealed that the thesis—titled “Making U.S. Security and Privacy Rights Compatible”—included improperly attributed language from sources like The Washington Post, the 9/11 Commission Report, ACLU reports, and a book penned by former President George W. Bush titled “Decision Points.”

CNN reported that Clarke received a letter from the school’s dean, Cdr. Paul Rasmussen, in July which stated that his thesis violated the institution’s honor code and gave him 100 days to revise the paper.

Although Clarke has not issued an official statement, he defended himself on a radio show after the plagiarism allegations surfaced in May.

“They’re saying certain words and phrases I should have put quotation marks around. OK, alright, fine. Maybe from a formatting standpoint the thesis isn’t perfect, but the content is there,” he stated, according to CNN.

The news outlet said it contacted Clarke for comments on its original plagiarism story. Instead, the former sheriff responded on Twitter, alleging that KFile also targeted Monica Crowley and Rand Paul.

In the past, David Clarke has come under fire for inmate deaths and inhumane conditions inside Milwaukee County Jail, as well as for his outlandish remarks about groups like Black Lives Matter. His actions were magnified when he became an avid Trump supporter during the 2016 presidential election.

Earlier this year, it was reported that the Trump administration was eyeing Clarke to become an assistant secretary in the Department of Homeland Security, but it was later revealed that they decided not to consider him for the role.